Basically, the tool acts as a wrapper for the UpdateWP file, and contains all the updates and their language packs. Using this tool has the same risk as using the manual cab method, so keep in mind that I'm not responsible for the chance something goes wrong, despite that being very low.

Download it over here. Please do not hotlink, link to this page instead. Thanks. Also, if you have issues with it, feel free to tinker with the source code to find your problem. It's a huge mess, but it should be easy enough to follow and patch if necessary.

If you have issues with about or wallpaper not opening, you have language pack issues. There's info here about that.

FAQ

I'm getting a lot of these, so please read these before contacting me. I don't mind mail, but the more time I spend on that, the less time I spend working on neat WP stuff ;)

Q: Is XXXX device supported?
A: Yes. This is completely device independent. The update works using the UpdateWP created by Microsoft, so it's roughly the equivalent of Zune updating.

Q: Do I need unlock? Will it lock my phone?
A: This works on all WP7 devices, regardless of software, jailbreak, SIM unlock, etc. Do read this info if you have an old OS version and are jailbroken, though.

Q: Can I update a custom ROM?
A: Yes, but I don't recommend it. Small updates, such as 8860 and 8862, should be fine.

Q: It says it's not a Win32 application!
A: Windows XP requires a special build for legacy purposes.

Q: Can I restore to 7.5?
A: Nope. Microsoft disabled OS downgrading. Keep that in mind before updating if you think you might want to downgrade ever.

Q: Settings/About/Something isn't working!
A: You don't have the right language packages installed. The info on that is here.

Q: You bricked my phone!
A: No, that's highly unlikely. Chances are the wrong packages were installed, and with a little work, your device can be good as new. Try the link above for info and package lists.

Again, hope you enjoy it, and if you appreciate it, feel free to support my work ;)